Engine piston



fiana 22, 1929. 1,699,622 H. J. Mass INVENTOR fikeowd Mas ATTORNEY Jan; 22, 1929. 1,699,622

H. J. NESS ENGINE PISTON Filed April s, 1926 2 Shets-Sheet 2 gum/W001 3& 4 8 Gum/MA;

Patented Jan. 22, 1929.

UNITED STATES PATENT OFFICE.

HAROLD J. HESS, OF JERSEY CITY, JERSEY, ASSIGNOR, BY MEBNE ASSIGHIENTS,

TO THE CLEVELAND 'rnus'r comramr, omo.

OI CLEVELAND. OHIO, A CORPORATION OF ENGINE PISTON.

Application filed April 8,

also a modified form of anchorage for the in-I set members.

' thepistons'are slit so as to My invention relates to enginepistons, and particularly to aluminum pistons of the split or slotted skirt type. The use of aluminum pistons in internal combustion engines is particularly desirable because of their li htness in weight and of their ability to dissipate heat. They are objectionable because of their large coeflicient of expansion, and to obviate this objection and lessen the clearance which would otherwise be required, the skirts of revent seizing in the cylinder when expanded from heat or too greatlooseness when contracted or cold. The ob'ection to slit istons is that it is extremely di cult to prodhce pistons of definite d1- mensions because they must be machined before bein slit, and, when slit, because the slitting re ieves strains which have been set up in the metal of theskirt, the are extremely apt to assume forms out o a true circle. Thereafter, because the slit in the, sk1rt permits a springing action between the portions of the skirt, separated by the slit, accurate machining is extremely difiicult, if not impractical. Further, under the hammering of actual use they have a tendency to distort out of shape as well as to collapse under the power or compression strokes.

My, invention obviates these difficulties,

since the advantages of the lightness and close fit of the aluminum split skirt pistons are'reta-ined, but the disadvantages are eliminated. I accomplish this by formingthe skirt pf my improved piston so that whenslit the slit portions of the walls have a mechanical interlock which gives the walls adequate su port during machining or when in use, w 110 at the same time seizing is prevented just as in the splitskirt type. -My nvention also comprises various features which I shall hereinafter describe and claim.

Referring to the drawings, in which I have shown a piston of a type largely used inauto- !926. Serial No. 100,487.

mobile internal combustion engines, the head 2 has depending webs 3 which connect the head 2 w1th the piston pin bosses 4. Substantially at right angles to the pin bosses 4 are the plates 5, which are curved from their points of juncture 6 with the skirt-7 to give a slightly resilient connection betweenthe skirt 7 and plates 5. While the upper portions 7 of the' skirt do not extend circumferentially beyond their points of juncture 6 with the plates 5 in the region of the piston pin bosses 4, below the plates 5 the skirt is in the form of a substantially complete circle. This lower circular portion 7 is interrupted where desired by a slot 8, here shown as extending from the lower to the upper edge of the skirt in one of the portions between the plates 5, and intersecting the space 9, which lies between ,the upper edge of the skirt 7 and the piston head 2.

Extending across the slot 8' is a plate 10- or groove 12 in the opposite edge of .the slot 8. I have found it desirable to make theplate 10 of steel and to form the recess 12 by inserting a piece 13 of steel of U-sha e in cross-section in the opposite edge 14 o the slot. The two-edges 11 and 14 of the slot 'are thickened or reinforced at 15 so as to provide ample metal in which to anchor the metal pieces 10 and 13. .To prevent the plate 10 from becoming jammed in the groove 12, particularl during assembly of these parts in the mol the plate 10 has lugs 10 struck from its outer edge which enable the plate to be cated without jamming. 7

During the casting operation, in which the metal pieces 10 and 13 maybe secured in position, a core piece is preferably inserted between the reinforced portions 15 to form a continuous slot along the inner face of the plate 10. As is shown in Figs. 3 and 4, the grooved piece 13 when cast has'the upper and lower ends of the groove closed at 13 to revent the flow of metal into the oove 12. A ter the casting operation the skirt on the exterior of the plate 10 is preferably cut through, thusformingfthe slot 8 on opposite sides of the metal late 10. This relieves the strains in the meta resulting from the casting o ration, and permits the metal on either s de of the cut to move relatively to the art on the other side. The support aflord by properly lotion and recess engagement obviously permits.

radial as well as circumferential movement of the skirt.

In Fig. 5 I have shown a modified form of my invention in which the tongue 20 and the member 23 are secured to the body' of the piston by means of discontinuous reinforcing portions 25 instead of by the continuous reinforcing portions 15 as is shown in Figs. 1 and 2. The slotted portion of the skirt is indicated at 18.

When pistons in use they are accurate fit than the types of split skirt pistons now commonly used, as the mechanical interlock supports the piston at the slot, prevents distortion and distributes the thrust of the power stroke, and results in givin a uniform bearing on the cylinder'walls. lily thus maintaining the piston in substantially true circular form, the oil is prevented from working up along the skirt past the oil wiper ring of the piston head. a

The terms and expressions which I have employed are used as terms of description and not of limitation, and I have no intention, in the use of such terms and-expressions, of excluding any equivalents of 'the features shown and described, or portions thereof, but recognize that various modifications are possible within the scope of the invention claimed.

What I claim is:

1. An aluminum alloy piston havin a head; a skirt; piston pin bosses connecte to the head and the skirt; the skirt having a vertically extending line of division; and means in the region of said line forming an arc-shaped bearing struck from the vertical axis of the skirt between the divided parts supporting such parts against collapse but permitting relative movement between the two parts of the skirt separated by the said line of division.

2. An aluminum alloy piston having a head; a skirt; members connecting the head and the skirt; the skirt having a vertically of my improved design are found to have a much more along one edgeopposite side of the slot extending slot; a member fixed to the skirt along one edge of the slot and extending across said slot, and having a movable engagement in a recess in said skirt on the opposite side of the slot, whereby the parts of the skirt on opposite sides of the slot support each other and are capable of relative movement with regard to each other.

3. An aluminum alloy piston having a head; a skirt; piston pin bosses connected to the head and the skirt; the skirt having a vertically extending slot; a member fixed to the skirt alon one side of the slot and extending across sai slot; a recessed member secured to the opposite side of the slot and having a projection and recess engagement with the free edge of said 'first' mentioned member; said members providing means for supporting the parts of the skirt divided by the slot while permitting relative movement therebetween.

4:- An aluminum alloy piston having a head; a skirt; members connecting the head and the skirt; the skirt having a vertically extending slot; a member fixed to the'skirt of the slot and extending across the slot; the said member having a projection and recess engagement with the other edge of the slot, the said on agement providing supporting means for t e parts of the piston on the op osite side of the piston and permitting relative movement therebetween.

5- An aluminum alloy piston having a head; a skirt; piston pin bosses connected to the head and the skirt; the skirt having a vertically extending slot; a steel insert secured in one edge of the slot; a recessed member secured in the other edge of the slot; the insert and member having a projection and recess enga ement forming a support for the parts of t e skirt on either side of the slot while permitting relative movement-therebetween. i

6. An aluminum alloy piston having a head; a skirt; piston pin bosses connected to the head and the skirt; the skirt having a vertically extending slot and thickened portions therealong; a steel insert secured in one edge of the slot adapted to extend across said slot and seat in ,a recess in the skirt on the and means for limiting the entry of the insert into the recess to prevent jamming of the insert therein.

HAROLD J. NESS. 

